To provide many audio functions by the small number of audio jacks and to save a space by outputting input through a selector to the audio jack and controlling the selector.

This circuit is constituted of a sound circuit 1, selectors 2 and 3, a speaker 4, an audio jack 5 and a control circuit 6. Normally, by the control circuit 6, the selector 2 is turned to OUT 2-3, the selector 3 is turned to HP 3-1 and made to function as a headphone terminal and sound is outputted from a headphone and the speaker 4. At the time of using it as a LINE-IN jack function, the selector 2 is switched to IN 2-2, the selector 3 is switched to SP 3-2 and output is performed only from the speaker. At the time of using it as a MIC jack function, the selector 2 is switched to MIC 2-1 and the selector 3 is switched to SP 3-2. Thus, the space is saved without reducing the audio functions.